Rotary-drill bit



Char-'25s .5. fiwaz'm C. S. SWAIM ROTARY DRILL B IT Filed Dec. 9, i922Patented Oct. 7, 1924.

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ROTARY-DRILL BIT.

Application filed December 9, 1922. Serial Ito. 605,880.

To all whom it may concern:

Be it known that I, CHARLES S. SWAIM, a citizen of the United States,residing at Long Beach, in the county of Los Angeles and State ofCalifornia, have invented certain new and useful Improvements in Rotary-Drill Bits, of which the following is a specification, reference beinghad to the accompanying drawings.

This invention relates to improvements in bits for rotary drills and animportant object of the invention is to provide a device of thischaracter embodying a stem and a plurality of blades, the blades beingdetachably secured to the stem so that they may be readily removed topermit sharpening thereof. A further object of the invention is toprovide a device of this character having the blades detachablyconnected with the stem and a locking member for the blades for holdinthe same in position within the stem which 1s protected by the blades toprevent destruction thereof by contact with the ground.

These and other objects I attain by the construction and arrangementshown in the accompanying drawings wherein for the purpose ofillustration is shown a preferred embodiment of my invention and whereinlike reference characters designate like parts throughout.

In the drawings Figure 1 is a side elevation of a bit constructed inaccordance with my invention;

Fignre 2 is a vertical sectional view therethrough;

Figure 3 is a section on the line 33 of Figure 1;

Figure 4 is a fragmentary side elevation, parts being broken awayshowing a pre ferred construction; and

Figure 5 is a vertical sectional view taken through the type of bitshown in Figure 4.

Referring now more particularly to the drawings, the numeral 16indicates a drill stem having a central bore 11' extending entirelytherethrough and adapted at one end for engagement with a drill pipe 12of a rotary drilling outfit. The lower end of the stem is enlarged, asindicated at 13, and this enlargement terminates in a reduced andpreferably tapered threaded portion 1d. The enlargement is provided withlongitudinally extending channels 15 which are of greater width at theirbases, indicated at 16, than at the point where they open through thesides of the enlargement, being preferably in the form of a dove-tail.ny suitable number of the channels 15 may be provided, in the presentinstance three thereof being disclosed. These channels open through thelower end of the-enlargement and are adapted for the reception ofcorrespondingly shaped inner edges of the shanks 17 of blades 18 so thatthe blades may be entered in the channels'and when so entered will beextended radially from the stem, the channel engaging portions of theblades being indicated at 19. The channel engaging portions are ofsubstantially the same length as the length of the channels so that whenthey are fully entered in the channels the lower ends thereof willsubstantiallycoincide with the lower end of the stem, and moreparticularly with the lower end of the enlargement 13 thereof. The bladeshank extends below the lower end of the enlargement 13 and has itslower end provided with an inward extension 20 so that when the bladesare all in position in the stem, these extensions approach and nearlyengage one another in spaced relation to the bottom of the enlargement13. These extensions form the blade proper and have their lower endsarcnately curved, as at 21, and have their lowest points at the innerlower end of the extension, as indicated at 22. The lower ends of theextensions are angled forwardly in the direction of rotation from apoint spaced slightly I above the lower edge thereof, as at 23.

The formation of the extensions 20 provides between the lower end of theenlargement 13 and the upper ends of the extensions a space for thereception of a looking member 24 for maintaining the blade; in position.This locking member as herein shown comprises a frusto-conical memberhaving a tapered threaded bore for coaction with the taperedscrew-threaded extension 14 of the stem 10, and is provided in the sidewalls thereof with openings 25 in which a bar or the like may beinserted between the blades to rotate the same. This locking member whenthreaded upon the extension 14 and firmly seated against the lower endof the enlargement 13, looks the blades 18 in position within thechannels 15, and the locking member, it will be noted, is eflec -tuallyprotected by the blades. The lower end of the locking member is open soas to permit fluid passing through the bore 11 of the stem to pass outand about the blades to wash out rock, dirt and the like upwardly out ofthe path of the blades. The locking member 24: is preferably providedwith some means for preventing rotation thereof when in appliedposition, as a set screw 26 for extending through the wall thereof toengage in the extension 14- This locking member 2% serves to preventaccidental loss of the blades during raisingor lowering of the bit inthe well. It will be obvious that when the bit, and more particularlythe blades thereof, are at rest upon the bottom of the well and theseblades have superimposed thereon the weight of the drilling string orpipe, it will be impossible for the blades to move downwardly in theirgrooves. Accordingly, any tendency of the locking member 24 t0 unscrewor release from the bottom of the stem during the drilling operation isprevented and accordingly the positioning of the locking member so as toprevent loss of the blades during withdrawal of the bit from the" wellis assured.

it will be obvious that the blades of a cutter constructed in accordancewith the foregoing may be readily applied to the stem or removedtherefrom for sharpening and that lighter or heavier blades suitable tothe type of bore being made ma be substituted as desired. It willlikewise be obvious that many changes are possible in the constructionof the same without in any manner departing from the spirit of myinvention, for example, the channels 15 may be tapered from the lowerend to the upper ends thereof so that the blades when started by the tapof a hammer may be readily removed therefrom. In this type ofconstruction I prefer that the channel engaging portions 19 of theshanks 17 of the blades be made of such construction that they projectslightly beyond the lower end of the enlargement 13 to be engaged andheld in position by the locking member 2d. This construction will permitadjustment of the blades to compensate for wear of the walls of thechannel and the channel engaging portions 19 and insure a tight titbetween the blades and stem at all times.

I claim 1. lln a rotary drilling tool, a stem provided in its side withlongitudinal extending channels openin through the lower end thereof,blades having shanks engaged in said channels, and a locking memberengaged with the lower end of the stem and maintaining said blades inposition in said channels, the blades being provided at their lower endswith portions extending inwardly beneath the locking member and havingtheir inner edges approximating one another, said portions limitingdownward movement of the looking member upon the stem when the stem issupported by the blades.

2. In a rotary drilling bit, a stem provided in the side wall thereofwith grooves opening through the lower end thereof, said grooves beingsubstantially dove-tail shaped in cross section and taperinglongitudinally toward the upper ends thereof, blades having theircutting faces arranged below the stem and having shanks provided attheir inner edges with correspondingly shaped portions for engagement insaid grooves, and a locking member engageable with the lower end of thestem and adapted to abut the lower ends of said groove engaging portionsto maintain the same in position within the grooves.

3. In a rotary drilling bit, a stem provided in the side wall thereofwith grooves opening through the lower end thereof. blades havingshankportions engaged in said grooves, 'a threaded extension on said stem atthe lower end thereof, a locking member having threaded engagement withthe extension and abutting the shank por tions of the blades to shiftthe same longitudinally of the grooves, and extensions on said bladeslimiting downward movement of the locking member on the extension whenthe stem is supported by the blade.

In testimony whereof ll hereunto afiix my signature,

CHARLES S. SVJAIM.

